Water treating composition



Patented Nov. 13, 1951 UNITED STATES PATENT OFFICE 2,575,177 WATER TREATING COMPOSITION John W. Lefforge, Anniston, Ala., assignor to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Application December 15, 1947, Serial No. 791,934

12 Claims,

1 The present invention relates to improved water treating compositions and to an economically and commercially feasible method of producing where R1 and R2 are aliphatic and/or alicyclio radicals, at least one of which contains not less than 6 nor more than 10 carbon atoms and where R1 may also be hydrogen.

Another object of the invention is to provide a water treating composition of substantially increased solution rate Which contains a water soluble molecularly dehydrated sodium phosphate having a Na20/P205 molecular ratio of from 1.0 to 1.3,.an alkalinity adjusting agent which liberates a substantially water insoluble gas upon reaction with the above phosphate and an amine defined by the above general formula, which composition floats upon the surface of water treated therewith until dissolved, or at least partially sinks toward the bottom of the dissolving vat and then is refloated by the buoying action of the liberated gas until completely dissolved.

A further object is to provide a water treating composition including the above combination of ingredients which disintegrates and spreads over the surface of the water treated and thus provides a non-matting or non-lumping material which possesses a substantially improved solution rate over that of similar compositions not containing an amine.

.Lothel' objects and advantages of the present invention will be apparent to those skilled in the art as the description proceeds.

Water soluble sodium metaphosphate is a well known and widely used water treating compound which is available commercially in the form of glass, powder or flakes, but for various reasons which will be hereinafter indicated, these products have not been entirely satisfactory.

- For example, sodium hexametaphosphate in the form of broken glass is not convenient to handle and in addition is very slowly soluble. The flaked product readily goes into solution but is expensive to produce and has the objectionable property of sticking to or cutting the hands of the user. The powdered product mats up or lumps when added to water and settles to the bottom of the dissolving vat in the form of a sticky gummy mass which dissolves at .an extremely slow rate.

The matting tendency on the part of pow-' dered sodium hexametaphosphate may be counteracted partially by mixing therewith sodium carbonates and other gas liberating alkalinity adjusting agents, but this method of approach does not provide a satisfactory solution to the problem. For example, if such mixtures are added to water, matting or lumping does not take place to the extent that it occurs with powdered sodium hexametaphosphate per se, but the wetting rate of the phosphate powder and the gas liberation rate are so rapid that the buoying action of the gas is not of sufiicient duration to insure complete solution of the mixture. The result is that appreciable amounts of sodium hexametaphosphate sink to the bottom of the dissolving vat and form a phosphate residue which dissolves very slowly.

Heretofore, it hasbeen proposed to'solve the above problem by agglomerating mixtures of powdered sodium hexametaphosphate and sodium carbonates. This method achieved some measure of success, but it is subject to the disadvantage of being expensive and of causing an excessive amount of reversion which seriously impairs the water softening properties of the product.

I have made the surprising discovery that if finely divided sodium hexametaphosphate, sodium carbonate and an amine defined by the above general formula are intimately and homogeneously mixed together in the proportions hereinafter indicated, a water treating composition of substantially improved solution rate is provided which has none of the objectionable properties mentioned above. Thus, the resulting composition is in a very convenient form to handle,

that is, to take out of a container, measure and put into solution;it is also quickly soluble and does not mat up when introduced into water;

and it can be very easily and economically produced on a commercial scale.

The sodium carbonate in the above composition serves as an alkalinity adjusting agent and also as a means of developing carbon dioxide which causes the product to float on the surface of water. Thus, sodium carbonate liberates carbon dioxide by reaction with sodium hexametaphosphate and the liberated gas forms bubbles which attach themselves to the particles of the phosphate product. These bubbles buoy up the particles and cause them to float on the water surface until completely dissolved The amines of the present invention are somewhat water repellent and retard the wetting rate of the sodium hexametaphosphate particles and 2 this has the desirable effect of causing the bubbles produced by the liberated carbon dioxide to attach themselves to the above, particles with the result that the latter are buoyed up. and

floated on the surface of the water. The wetting l rate retarding action of the amines brings about a slower but more uniform reaction between thephosphate particles and the sodium carbonate and therefore the liberated gas is abletov float the particles upon the surface of the water for a. period long enough to effect. rapid solution thereof; These compounds also disperse any floating lumps of. the mixture which. may form on the surface and thus notonly aid in the prevention of matting but also increase the surface of the particles exposed] to the dissolving action of the water treated.

' The problems of matting and slow solution rate are not limited to sodium hexametaphosphate as they occur in all of the water soluble molecularly dehydrated alkali metal phosphates having an alkali, metal oxide/P205 molecular ratio of from about 1.0 to about 1.3 and it is to be understood that the present. invention is directed to all of the foregoing phosphates and particularlyto the sodium and potassium phosphates within the above range.

For amore complete understanding of the present invention reference is made to the following examples which illustrate the marked increase in solution rate obtained by incorporating an amine of the type hereinbefore indicated with mixtures of sodium carbonate and water soluble molecularly dehydrated sodium phosphates having a Naz/P2O5 molecular: ratio within. the range of from 1.0 to 1.3.

Example I A finely divided phosphate product (Calgon) composed of approximately 80.8% by weight of sodium hexametaphosphate, 11.8% by weight of tetrasodium pyrophosphate and 7.4% by weight of sodium acid pyrophosphate was thoroughly mixed with. 6% by weight of sodium carbonate toform asubstantially homogeneous mixture of these materials. A -gram sample of the product was added to abeaker containing a liter of water and the time required to completely dissolve this material without agitation was determined. It was found that a substantial proportion of the sample rapidly dissolved'during the gas liberating stage, but as soon as this was over, a portion thereof sank to the bottom of the beaker and formed a phosphate residue which dissolved so slowly that a total of 11 minutes was required for complete solution.

A similar mixture was prepared except that 0.01% by weight of heptyl amine was uniformly blended therewith.

A 5-gram sample of this product was introduced into a liter of water and its solution rate determined inthe manner described above. It was found that instead of Setting free carbon dioxide all at once and leaving a slowly dissolving 4 residue on the bottom of the beaker, the amine caused the phosphate material to spread out on the surface of the water and liberate the above gas slowly and uniformly with the result that the product floated and dissolved completely within a period of 4 minutes.

Example II A finely divided phosphate composition consisting essentially of sodium septaphosphate (NasPvOzalwas thoroughly mixed with 6% by weight oisodium carbonate and a 5-gram sample ofthe resulting product was added to a liter of water for the purpose of determining its solution rate. As in Example I a substantial amount of the product rapidly dissolved during the gas liberation period, but a slowly dissolving residue was formed on the bottom of the beaker and it' required 16 minutes to achieve complete solution of the entire sample.

The above experiment was repeated using the same composition t'o which 1% by weight of heptylamine had been added and intimately mixed. The resulting product dissolved completely without agitation in a period oftwo minutes.

The above examples show that-the problem of matting or lumping is solved by the addition of heptyl amine and that the solution rate of mixtures of sodium carbonate with the above phos phates is thereby increased to a surprisingdegree.

The chemical composition of the Water treating product may be varied widely to meet specific requirements, but for optimum results from the standpoint of detergent and water softening properties, it is preferred to maintain the components thereof substantially within the limits specified in the. following formulation.-

Per cent by weight- Phosphate composition; 96 to 88 Gas liberating alkalinity adjusting compound Amine 0.01 to 2 Expressed in terms of pH, it is essential, when employing a gas liberating alkalinity adjusting agent, that the composition be so proportioned as to yield a pH in 1% solution of about 6.7 to 8.0 and within this range a pH of'7;8 1spreferred. However, if a gas liberating compound is included in the composition which does not depend upon a particular pH of solution to liberate a suificient amount of gas to float the product, then pH is not a critical factor and therefore compositions having a pH outside of the, above range may be employed. Thus, in its broadestaspect, the present invention is directedto water treating products having the following range of' compositions.

Per cent byweight Phosphate composition s ito96 Gas liberating compounds 20 to: 2.

Amine 0.01 to 2 Phosphate Composition as used above covers water soluble molecularly dehydrated alkali metal phosphates havingv an. alkali metal. ox-- ide/PzOa molecular ratio of about 1.0 to about.

tridge et al. which is reported in vol. 63 of the J. Amer. Chemical Society, 1941. The expression Gas Liberating Compounds includes alkalinity adjusting agents such as sodium percarbonate, sodium carbonate, sodium bicarbonate or other compounds or combinations of compounds which hydrolyze or react together in the presence of water to yield a substantially water insoluble gas.

The amines employed in the production of non-matting, rapidly dissolving water treating products of the above type are defined by the general formula recited earlier herein. Illustrative examples of specific amines within the scope of the above formula which have been successfully employed in the preparation of the above products are hexyl amine, heptyl amine, octyl amine, decyl amine, cyclohexyl amine and dicyclohexyl amine. Of this group, the most satisfactory results are obtained with heptyl amine.

The amount of amino-compound employed in the water treatin product may fluctuate considerably, but it is preferably maintained within the range of about 0.01% to about 2% by weight. amount varies with the amine selected and in general the longer the alkyl chain or the higher the molecular weight, the smaller is the amount of amine required. In the case of heptyl amine, the best results are obtained by using this material in an amount equivalent to about 1% by weight.

In compounding the above product, the components may be mixed together in any desired order so long as thorough and uniform mixing is obtained.

The particle size of the alkali metal phosphates is not critical, but it is desirable to use material not coarser than 50 mesh, and preferably not coarser than 100 mesh.

The above description has been limited to compositions consisting essentially of water soluble molecularly dehydrated alkali metal phosphates, gas-liberating compounds which yield a substantially water insoluble gas upon contact with water and amines defined by the above general formula. The invention, however, is not restricted thereto as various alkalinity adjusting compounds in addition to those specifically mentioned may be incorporated in the above compositions. For example, caustic soda, sodium sulfate, sodium bisulfate, sodium bisulfite, sodium metasilicate, trisodium orthophosphates, sodium pyrophosphates, sodium polyphosphates having a NazO/PzOs molecular ratio above 1.3, and mixtures of these,, and also the corresponding potassium salts may be employed if desired.

Where the gas-liberating compound yields gas upon contact with water irrespective of the pH of the composition, the above alkaline salts may be used in any desired proportions, but this is not true where gas-liberating alkalinity adjusting agents are employed. Thus, if sodium percarbonate, sodium carbonate, sodium bicarbonate or equivalent salts are used, the quantity of the alkalinity adjusting compounds must be so proportioned as to provide a composition having a pH in 1% solution not exceeding about 8.0, otherwise matting will occur. The reason for this is that a pH above 8 either prevents the reaction between the phosphates and the alkalinity adjusting agent from occurring or it retards the reaction rate to a point where the gas is not liberated rapidly enough to float the product. The result is that the phosphate composition sinks to the bottom of As would be expected, the optimum 6 the dissolving vat and forms a very slowly. dissolving residue.-

The present invention is limited solely by the claims attached hereto as part of the present specification.

I claim:

1. A substantially non-matting water treating composition consisting essentially of a substantially homogeneous mixture of the following materials in the indicated proportions: a water soluble molecularly dehydrated sodium phosphate having a sodium oxide/P20 molecular ratio of about 1.0 to about 1.3, 8 0%-96% by weight; a compound selected from the group consisting of sodium carbonate,- sodium bicarbonate and sodium percarbonate, 20%-2% by weight; a primary aliphatic amine having 6 to 10 carbon atoms, 0.01%-2% by weight.

2. A substantially non-matting water treating composition consisting essentially of a substantially homogeneous mixture of the following materials in the indicated proportions: a water soluble molecularly dehydrated sodium phosphate having a sodium oxide/P205 molecular ratio of about 1.0 to about 1.3, 88%-96% by weight; a compound selected from the group consisting of sodium carbonate, sodium bicarbonate and sodium percarbonate, 4%-10% by weight; a primary aliphatic amine having 6 to 10 carbon atoms, 0.01%-2% by weight.

3. A substantially non-matting water treating composition in accordance with claim 2 wherein the water soluble molecularly dehydrated sodium phosphate is sodium hexametaphosphate.

l. A substantially non-matting water treating composition in accordance with claim 2 wherein the water soluble molecularly dehydrated sodium phosphate is sodium septaphosphate.

5. A substantially non-matting water treating composition in accordance with claim 2 wherein the primary aliphatic amine is hexylamine.

6. A substantially non-matting water treating composition in accordance with claim 2 wherein the primary aliphatic amine is heptylamine.

7. A substantially non-matting water treating composition in accordance with claim 2 wherein the primary aliphatic amine is octylamine.

8. A substantially non-matting water treating composition in accordance with claim 2 wherein the primary aliphatic amine is decylamine.

9. A substantially non-matting water treating composition in accordance with claim 2 wherein the primary aliphatic amine is cyclohexyl amine.

10. A substantially non-matting water treating composition consisting essentially of a substantially homogeneous mixture of sodium hexametaphosphate, about 6% by weight of sodium carbonate and about 0.01% by weight of heptylamine.

11. A substantially non-matting water treating composition consisting essentially of a substantially homogeneous mixture of sodium septaphosphate, about 6% by weight of sodium carbonate and about 0.01% by weight of heptylamine.

12. A substantially non-matting water treating composition consisting essentially of a substantially homogeneous mixture of the following materials in the indicated proportions: a water soluble molecularly dehydrated sodium phosphate having a sodium oxide/P205 molecular ratio of about 1.0 to about 1.3, %-96% by weight; a compound selected from the group consisting of sodium carbonate, sodium bicarbonate and sos dimn percarbonate,:20%-'2% by-weight; an-amme REF-ERENGES CITED of the following general formula: The following references are of record in the R}\ file ofc'his patent:

/NH 5 STATES PATENTS R2 Number Name Date wherein R1 is'se'lected from the group "consisting Rte-"1391 9 Hall 0015.38, 1935 of hyd-rogen, aliphatic and cyclohexyl radicals I 3 5 iziml 6,1934 and R2 is selected from the group eons'isting of 2,0 4,380 Flett Mar. 23, 1937 aliphatic and cyelohexyl radicals -a't least oneof 10 2,244,158 Hubbard et a1 June 3, 1941 Said aliphatic radicals containing not -1ess "than fi 2;4l4,969 Moose Jan. 28, 1947 normore than 10 carbon atoms when f=R1 and R2 I are notcycl'o'hexyl radicals, -'0.0-1'%-'2% by weight. FOREIGN PATENTS Number Country Date JOHN 1:5 I 52836?! Great Britain :Nov. 12, 1940 Certificate of Correction Patent No. 2,575,177 November 13, 1951 JOHN W. LEFFORGE It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 6, line 53, for the claim reference numeral 2 read 12; line 54, strike out primary aliphatic;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the casein the Patent Ofiice.

Signed and sealed this 19th day of February, A. D. 1952.

THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

1. A SUBSTANTIALLY NON-MATTING WATER TREATING COMPOSITION CONSISTING ESSENTIALLY OF A SUBSTANTIALLY HOMOGENEOUS MIXTURE OF THE FOLLOWING MATERIALS IN THE INDICATED PROPORTIONS: OF WATER SOLUBLE MOLECULARLY DEHYDRATED SODIUM PHOSPHATE HAVING A SODIUM OXIDE/P2O5 MOLECULAR RATIO OF ABOUT 1.0 TO ABOUT 1.3, 80%-96% BY WEIGHT; A COMPOUND SELECTED FROM THE GROUP CONSISTING OF SODIUM CARBONATE, SODIUM BICARBONATE AND SODIUM PERCARBONATE, 20%-2% BY WEIGHT; A PRIMARY ALIPHATIC AMINE HAVING 6 TO 10 CARBON ATOMS8 0.01%-2% BY WEIGHT. 